Fix badcast in event::isGestureEvent

Bug: 11676314

Cherry pick https://codereview.chromium.org/35153013.

Change-Id: I141d6fe56410e2c44631b17e537f52ab7a75d3d6

5 files changed, 22 insertions, 3 deletions

diff --git a/Source/core/dom/Event.cpp b/Source/core/dom/Event.cpp
index 1b714f753..f066f56c6 100644
--- a/Source/core/dom/Event.cpp
+++ b/Source/core/dom/Event.cpp
@@ -138,6 +138,11 @@ bool Event::isTouchEvent() const
     return false;
 }
 
+bool Event::isGestureEvent() const
+{
+    return false;
+}
+
 bool Event::isDragEvent() const
 {
     return false;
diff --git a/Source/core/dom/Event.h b/Source/core/dom/Event.h
index 7875b1e23..3d4695fd9 100644
--- a/Source/core/dom/Event.h
+++ b/Source/core/dom/Event.h
@@ -126,6 +126,7 @@ public:
     virtual bool isFocusEvent() const;
     virtual bool isKeyboardEvent() const;
     virtual bool isTouchEvent() const;
+    virtual bool isGestureEvent() const;
 
     // Drag events are a subset of mouse events.
     virtual bool isDragEvent() const;
diff --git a/Source/core/dom/GestureEvent.cpp b/Source/core/dom/GestureEvent.cpp
index a4f5cf8f5..735036eaf 100644
--- a/Source/core/dom/GestureEvent.cpp
+++ b/Source/core/dom/GestureEvent.cpp
@@ -90,6 +90,11 @@ const AtomicString& GestureEvent::interfaceName() const
     return UIEvent::interfaceName();
 }
 
+bool GestureEvent::isGestureEvent() const
+{
+    return true;
+}
+
 GestureEvent::GestureEvent()
     : m_deltaX(0)
     , m_deltaY(0)
@@ -110,7 +115,7 @@ GestureEventDispatchMediator::GestureEventDispatchMediator(PassRefPtr<GestureEve
 
 GestureEvent* GestureEventDispatchMediator::event() const
 {
-    return static_cast<GestureEvent*>(EventDispatchMediator::event());
+    return toGestureEvent(EventDispatchMediator::event());
 }
 
 bool GestureEventDispatchMediator::dispatchEvent(EventDispatcher* dispatcher) const
diff --git a/Source/core/dom/GestureEvent.h b/Source/core/dom/GestureEvent.h
index a0d6f2edd..b630ae934 100644
--- a/Source/core/dom/GestureEvent.h
+++ b/Source/core/dom/GestureEvent.h
@@ -41,6 +41,8 @@ public:
 
     void initGestureEvent(const AtomicString& type, PassRefPtr<AbstractView>, int screenX, int screenY, int clientX, int clientY, bool ctrlKey, bool altKey, bool shiftKey, bool metaKey, float deltaX, float deltaY);
 
+    virtual bool isGestureEvent() const OVERRIDE;
+
     virtual const AtomicString& interfaceName() const;
 
     float deltaX() const { return m_deltaX; }
@@ -69,6 +71,12 @@ private:
     virtual bool dispatchEvent(EventDispatcher*) const OVERRIDE;
 };
 
+inline GestureEvent* toGestureEvent(Event* event)
+{
+    ASSERT(event && event->isGestureEvent());
+    return static_cast<GestureEvent*>(event);
+}
+
 } // namespace WebCore
 
 #endif // GestureEvent_h
diff --git a/Source/web/WebPluginContainerImpl.cpp b/Source/web/WebPluginContainerImpl.cpp
index 65d50f581..e24241076 100644
--- a/Source/web/WebPluginContainerImpl.cpp
+++ b/Source/web/WebPluginContainerImpl.cpp
@@ -194,8 +194,8 @@ void WebPluginContainerImpl::handleEvent(Event* event)
         handleKeyboardEvent(toKeyboardEvent(event));
     else if (eventNames().isTouchEventType(event->type()))
         handleTouchEvent(static_cast<TouchEvent*>(event));
-    else if (eventNames().isGestureEventType(event->type()))
-        handleGestureEvent(static_cast<GestureEvent*>(event));
+    else if (event->isGestureEvent())
+        handleGestureEvent(toGestureEvent(event));
 
     // FIXME: it would be cleaner if Widget::handleEvent returned true/false and
     // HTMLPluginElement called setDefaultHandled or defaultEventHandler.